The invention relates to a drilling apparatus comprising a drilling tool receivable in a drilling machine and having a drill shaft, and a drilling head with a drilling plate located at the free end of the drill shaft of the drilling tool.
A drilling apparatus for producing drilled holes provided in the base region with an undercut, is known. The undercut is produced due to pivotal movement of a drill with a broadened drilling head. An expansible plug having an expansible portion that positively engages the undercut can then be inserted into such a drilled hole.
DE-OS No. 33 40 090 discloses a drilling apparatus for producing a drilled hole having an undercut. The drill shaft in this known drilling apparatus is guided in a sleeve with a relatively large amount of play, and the drill shaft can be pivoted inside the sleeve. This has the disadvantage, however, that the drill tool is deflected during the drilling operation, especially when it meets iron rods or other particularly hard components. The deflection of the drill tool can produce distortions in the drilled hole. A particular disadvantage consists in that the drill shaft itself does not form a pivot axis.